Daewoo Nexia Quiz
Heating, Ventilation and Air Conditioning System

The high-pressure switch (pressure relay) is located on the rear cover of the compressor and is connected to the discharge line. The switch protects the compressor from excessive discharge pressure and reduces refrigerant loss through the pressure relief valve. The normally closed pressure relay opens the compressor

In this manual: Heating, Ventilation and Air Conditioning System
OWNER'S MANUAL — 12Vehicle Maintenance — 15Maintenance — 16Engine (Single Overhead Camshaft) — 50Engine (dual overhead camshafts) — 45Cooling System — 14Fuel and Exhaust Systems — 31Engine Electrical Equipment — 16Ignition System — 8Electronic Control Unit and Sensors — 12Clutch — 11Five-Speed Transmission and Final Drive RPO MM5 — 16Automatic Transmission — 46Wheels and Tires — 17Front Suspension — 13Front Axle Drive Shafts — 10Rear Suspension — 12Brake System — 54Body — 127Heating, Ventilation and Air Conditioning System — 21Electrical System — 7Wiring Diagrams — 25
~2min read

GENERAL INFORMATION.

Low-Pressure Switch

Some vehicles use a low-pressure switch (pressure relay) to protect the compressor. It may be located on the rear cover of the compressor or connected to the refrigerant line. The switch operates when refrigerant is lost or the refrigerant charge in the A/C system is low. This switch also prevents compressor operation at low

ambient temperatures.

Compressor Switch and Power Steering Pressure Sensor

On some vehicles, a normally closed compressor switch responds to increased load from the power steering pump to maintain a stable idle speed. When maneuvering at low speed, pressure in the power steering system rises and the compressor switches off automatically. In other applications, a power steering load sensor

(normally open pressure relay) is used. It closes when the power steering pump discharge pressure rises. The engine ECU responds to the relay signal and maintains a stable idle speed.

Low Pressure Switch.

Compressor Switch at Full Throttle

A switch located in the throttle linkage opens the electrical circuit of the compressor clutch relay and switches off the compressor at full throttle. On vehicles equipped with multi-point fuel injection, at full throttle the throttle position sensor (TPS) sends a signal to the ECU, which then

controls engagement of the compressor clutch.

A/C Delay Relay

Some vehicles have an A/C delay relay that switches off the

compressor during engine starting.


A/C Component Layout and Refrigerant Flow Diagram A. DISCHARGE LINE – FLOW OF HOT COMPRESSED REFRIGERANT VAPOR.

B. REFRIGERANT FLOW R-1.

C. SUCTION LINE – FLOW OF COLD REFRIGERANT VAPOR UNDER LOW PRESSURE.

D. LIQUID LINE – FLOW OF HOT LIQUID REFRIGERANT UNDER HIGH PRESSURE.

E. SERVICE PORT ON HIGH-PRESSURE SIDE.

F. SERVICE PORT ON LOW-PRESSURE SIDE.

6. PRESSURE REDUCING VALVE.

7. LOW-PRESSURE SWITCH

Before performing any A/C system service that involves removing lines or components, carefully read the applicable sections of this manual. When servicing the A/C system,

observe all safety precautions.

On some vehicles there is an A/C time-delay relay that switches off the

compressor during engine start-up.

Test yourself

A quick Daewoo Nexia quiz: every answer comes with an explanation and a link to the manual page.